Metallic product and method of manufacture thereof



M y 1964 J. K. EVANS ETAL 3,

METALLIC PRODUCT AND METHOD OF MANUFACTURE THEREOF fmzw. flmwm/ ATTORNEYS 2 Sheets-Sheet 1 P Jade y Filed May 15. 1961 May 26, 1964 J. K. EVANS ETAL 3,134,701

METALLIC PRODUCT AND METHOD OF MANUFACTURE THEREOF 2 Sheets-Sheet 2 Filed May 15, 1961 INVENTOR-S Jami Az'zgg [Va/w PkzZz/v flaaefidiwwz/ F75 ZA/MJM m I ATTORNEY 5 United States Patent 3,134,701 METALLIC PRODUCT AND METHGD OF MANUFACTURE THEREOF James K. Evans, Oley, and Philip S. Hanson, Wyomissing, Pa., assignors to The Beryllium Corporation, Reading, Pa., a corporation of Delaware Filed May 15, 1961, Ser. No. 110,215 6 Claims. (Cl. 148-115) The present invention relates to a new and novel composite product and method of manufacture thereof, and more particularly to a product having distinct portions of different physical characteristics.

It is often desirable to provide metallic components, various portions of which have different physical characteristics according to the particular application in which the device is to be employed. For example, in certain applications, it is desirable to provide a switch contact for an electrical circuit wherein the main body portion of the contact must have good electrical conductivity while at the same time it is desired to have a tip portion on the contact which can be readily magnetically attracted whereby the switch contact may be actuated by setting up a suitable magnetic field.

lIhe problem involved in this type of situation is that the substance forming the main body portion of good electrical conductivity is generally of a nature as not to be substantially afiected by a magnetic field, and accordingly, it is necessary to provide a suitable tip portion of a different material such as steel or other ferrous substances.

There are many other instances where it is desirable to provide a product which has portions of different characteristics as will be apparent to one skilled in the art. For example, it may also be desirable to form an electrical contact or for that matter any other member which will have a resilient springy portion with a more or less ductile end portion thereon. 'For example, a switch contact may be formed of springy material while the end portion thereof may be ductile to 'facilitate attachment of the spring to a suitable supporting means. Various other combinations of metallic materials will occur to one in the art to provide different physical characteristics such as corrosion resistance, electrical insulating properties, etc.

While it would seem that it would be a simple matter to merely weld two pieces of metal together to provide this desired end result, such is not the case in many practical applications. in the first place, when such welds are made according to most prior art processes, the area of weld may extend over quite a large area of the different portions of the contact thereby causing an intermixi-ng and intermingling of the materials of the two portions. This prevents the formation of two portions of sharp demarcation which have distinctly different physical characteristics which is highly important in the applications referred to.

An additional problem involved with articles formed of different metallic substances according to the present invention lies in the fact that it is usually desirable to heat-treat one of the substances to obtain certain desired characteristics while at the same time it is desired not to substantially alter the characteristics of another substance by such heat treatment.

According to the present invention, two or more strips of metallic material are rigidly secured to one another in such a manner as to form a composite body having distinct portions of different characteristics. This may be accomplished by Welding the members to one another along abutting edges thereof and in a narrow area to thereby restrict the effect of the welding operation upon the materials of the two members. By so forming the 3,134,701 Patented May 26, 1964 weld in a very narrow area it is possible to obtain a sharp demarcation between the compositions of the two materials and the amount of intermin-gling and intermixing of the crystals and physical properties of the two members is minimized.

Subsequent to securing the members together, the members are heat-treated in such a manner as to alter and obtain the desired physical characteristics of one of the members without substantially altering the physical characteristics of another of the members.

The resultant product of the aforementioned method steps is a composite strip of material from which finished articles of a desired configuration may be cut, the finished article thereby having distinct portions of different physical characteristics of the desired type.

An important feature of the invention is a novel method for rolling a composite strip including a soft member as well as a hard member. When two metallic portions having substantial diiferences in hardness are joined to one another and then rolled, there is a tendency for the softer material to elongate while the harder material will elongate at a much slower rate. This interaction occurring in two strips of material which may be side-by-side will cause the composite strip to tend to assume a curved shape in a longitudinal direction whereby it becomes extremely difficult to roll the strip since the strip does not tend to move in a straight line. In order to overcome this problem the present invention contemplates a novel arrangement wherein a strip of relatively soft material is interposed between -a pair of strips of relatively hard material. Accordingly, as the composite strip passes between pairs of squeezing rollers, the strips of relatively hard material at either side of the strip of material of relatively soft material will resist elongation and deformation of the central relatively soft strip thereby constraining the composite strip for movement in a straight direction.

A most important feature of the present invention is the fact that the materials chosen for the composite product are such that one of the materials has a heat treatment temperature range which is less than the heat treatment temperature range of the other material. Accordingly, after having formed the composite body, the body may be heat treated at a temperature within the lower heat treatment temperature range. This results in obtaining the desired qualities of the one material by the heat treatment operation while at the same time not substantially altering the characteristics of the other material.

While the composite product of the present invention may be formed of two members of different composition, the invention may be extended to include three or more members which are connected to one another as above discussed, and further heat treated in such a manner as to alter the characteristics of one or more of the members while not substantially altering the physical characteristics of another of the members.

An object of the present invention is toprovide a new and novel method of making a composite product which has portions having different physical characteristics.

Another object of the invention is to provide a method of making a composite product wherein there is a distinct demarcation between the portions having diiierent physical characteristics.

A further object of the invention is to provide a method of making a composite product including two or more metallic portions which are welded to one another and heat treated so as to obtain the desired properties of one portion without altering the properties of another portion thereof.

Still another object of the invention is to provide a novel method of making a composite product as aforesaid with a minimum of time, expense and effort.

Yet a further object of the invention is the provision of a unique article having distinct portions of different physical characteristics.

Other objects and many attendant advantages of the present invention will become more apparent when considered in connection with the specification and accompanying drawing, wherein:

FIG. 1 is a schematic flow diagram illustrating the steps of one form of the novel process of the present invention;

FIG. 2 is a schematic flow diagram illustrating the steps of a modified method according to the present invention;

IG. 3 is a perspective sectional view broken away illustrating a composite strip manufactured according to the method of the invention;

FIG. 4 is a perspective sectional view broken away illustrating another form of composite strip manufactured according to the present invention;

FIG. 5 is a perspective view of an article cut from the composite strip shown in FIG. 4;

FIG. 6 is a perspective sectional view broken away illustrating a still further form of composite strip according to the present invention; and

FIG. 7 is a perspective view illustrating an article formed from the composite strip shown in FIG. 6. Referring now to the drawings wherein li re reference characters designate corresponding parts throughout the several views, there is shown in FIG. 1 in a schematic manner a method for forming a composite strip from two separate strips of material.

Referring to the lefthand portion of this figure, two separate and individual strips of material 10 and 11 are fed to a welding station indicated generally by reference numeral 12 in side-by-side relationship. At the welding station, the two strips of material are brought into tight cdge-to-edge contact by a pair of rollers 14 and 15 which engage the outer edges of the two strips. As the strips pass between the rollers 14 and 15, they are welded to one another along the seam 16 therebetween as they pass beneath a hairpin-shaped conductor 20 and a pair of contacts 21 and 22.

This welding apparatus is preferably of the type shown in detail in US. Patent No. 2,887,560 and this type of apparatus produces welding by high-frequency resistance heating. This particular type of welding is very important in the present invention since it enables high production continuous welding to be carried out and the weld zone produced at the seam between the two strips is very narrow. The aparatus may actually operate at speeds on the order of 200 feet per minute while the weld zone will be retained to a narrow longitudinally extending strip less than A inch in width. This type of welding is sometimes referred to as forge welding since the two strips of material are forced together between rollers 14- and 15 as shown in FIG. 1.

This narrow restriction of the weld zone is very important since it minimizes the amount of intermixing and flow of the crystals of the material of each of the strips and accordingly a sharp demarcation is provided between the different materials of the strips.

The joined strips 10 and 11 as they emerge from the welding stations may or may not be subjected to an annealing heat treatment at an annealing station indicated by reference numeral 25. It is contemplated that in most instances the annealing stage will be unnecessary and this step has been indicated by dotted lines. The joined strips 10 and 11 are next passed into a rolling station indicated by reference numeral 26 wherein a plurality of rollers 27 may be provided, the joined strips passing between the rollers and having the thickness thereof reduced accordingly.

In a typical example, the thickness of the strips for welding purposes may be on the order of .040 inch, and

4 the joined strips are subsequently reduced to a thickness of approximately .010 to .016 inch as a result of passing between the rollers 27.

As a possible modification of the process, the joined strips 10 and 11 as they emerge from the welding station may be rolled, then annealed and subsequently re-rolled.

The joined strips next pass to a heat treatment station 28 where one of the strips is heat treated at a suitable temperature which is insufiicient to substantially alter the physical characteristics of the other strip. For example, strip 11 may comprise a beryllium copper alloy identified as Berylco 25, manufactured by the Beryllium Corporation, Reading, Pennsylvania, and having a chemical composition by weight of beryllium in the range of 1.80 to 2.05 percent, cobalt in the range of 0.20 to 0.30 percent and the balance being copper. The other strip 10 may be formed of steel. The heat treatment temperature for Beiylco 25 has lower and upper limits of approximately 500 F. and 850 F. respectively, the heat treatment range generally being conducted for practical purposes within a range of 550 F. and 650 F. with a preferred temperature of 600 F. The heat treatment temperature range of the steel which may for example be a carbon steel identified as SAE 1010 is 1650" F. to 1700 F. It is accordingly clear that the heat treatment (temperature range for the steel is considerably higher than that of the beryllium copper alloy, and accordingly, the composite strip is treated in the heat treatment temperature range of the beryllium copper alloy so as to increase the strength, hardness and electrical conductivity thereof while the physical characteristics of the steel are not substantially altered. In a typical example, the composite strip formed of Berylco 25 and SAE 1010 steel is heated for two hours at 600 F. when the composite strip has been merely cold-rolled without passing through an annealing treatment station. on the other hand, if such a composite strip has been annealed before rolling, the strip will be heated for approximately three hours at 600 F.

In a composite strip which may comprise Berylco 25 along with brass or steel, it is also possible to carry out a short term treatment wherein the composite strip may be treated at a temperature of approximately 800 F. for a period of 30 to 45 minutes.

Reference numeral 30 indicates the finished composite strip and after passing through the heat treatment station, the portion 11 has been precipation hardened while the portion it) retains substantially its original characteristics. Throughout the disclosure, the lines having small xs thereon indicate in a schematic manner the welded seam between the members of the composite products.

Referring now further to FIGS. 4 and 6, the manner of forming a finished article according to the present invention is further illustrated. As seen in FIG. 4, the composite strip 30 includes the strips 10 and 11 as shown in FIG. 1. A plurality of electrical contact members are laid out on the composite strip as shown in the dotted lines in FIG. 4, each of these contact members being indicated by reference numeral 35.

It is apparent that the contact members are cut out transversely of the longitudinal axis of the strip and that the contacts are cut out of immediately adjacent portions of the strip to minimize material loss.

One of the finished contact members is indicated by reference numenal 36 in FIG. 5, and as seen in this figure, the contact includes a main body portion 37 and a tip portion 38. The main body portion 37 has high electrical conductivity since it is formed of a precipation hardened beryllium copper alloy while the tip portion 38 forms a readily magnetically attracted end portion since it is formed of steel.

As discussed previously, these two strips 10 and 11 may be formed of many different materials in accordance with the characteristics which it is desired to obtain as long as the strips 10 and 11 are formed of materials having heat treatment temperature ranges, one of which is less than the other whereby the strip having the lower range may be heat treated to obtain certain desired characteristics without substantially altering the physical characteristics of the other strip.

As a further example of the invention, it may be desired to form a spring contact having a springy and resilient body portion and a ductile end portion for attachment to a suitable support means. In this case, the main springy body portion may be formed of Berylco 25 as discussed above, while the ductile end portion may be formed of brass. In such case, the heat treatment temperature range of the Berylco 25 is substantially less than that of brass which may be in the range of 1200 F. to 15 F., and accordingly, a composite strip formed of these materials may be heattreated at a temperature of 600 F. for approximately two hours thereby precipitation hardening the Berylco 25 strip without substantially altering the physical characteristics of the strip of brass.

As a further example of the present invention in forming a composite strip as shown in FIG. 1, a strip 10 may again be formed of steel while strip 11 may be formed of a beryllium copper alloy identified as Berylco 10 manufactured by The Beryllium Corporation of Reading, Pennsylvania. Berylco 10 is particularly noted for its physical properties at higher operating temperatures and has a chemical composition by weight of beryllium in the range of 0.40 percent to 0.70 percent, cobalt in the range of 2.35 percent to 2.70 percent, and the balance being copper. Berylco 10 has a heat treatment temperature range of approximately 900 to 950 F., and accordingly, the composite strip is heat-treated at 900 F. for approximately two hours. This heat treatment will not substantially alter the physical characteristics of the steel strip 10, and accordingly, the finished product will again comprise a precipitation hardened beryllium copper alloy strip along with a steel strip, the physical characteristics of which have not been substantially altered. It is, of course, evident that in each case where a composite strip is provided the finished article may be stamped or cut out of the composite strip as indicated in FIGS. 4 and 5 of the drawings.

In a further modification of the invention, two beryllium-copper alloys of different composition may be employed for forming a composite strip. In this modification, strip is formed of Berylco 10 while strip 11 is formed of Berylco 25. The composite strip in this case is heated to a temperature of 600 F. for approximately two hours thereby precipitation hardening the Berylco 25 strip while not substantially altering the physical characteristics of the Berylco 10 strip.

In a still further modification, the strip 10 may be formed of SAE 1010 steel, while strip 11 may be formed of a magnesium alloyhaving the trade name Mazlo SAE 502, this magnesium alloy having a heat-treat temperature range of approximately 450 to 750 F. Accordingly, the composite strip is heat treated at a temperature of approximately 600 F. for about two hours thereby heat-treat hardening the magnesium alloy while not substantially altering the characteristics of the steel.

Referring now to FIG. 2 of the drawings, a modified method according to the present invention is illustrated, wherein a central strip 40 of relatively soft material such as brass is provided, and is interposed between two strips 41 and 42 each formed of a relatively hard material such as Berylco 25. These strips are passed between a pair of rollers 45 and 46 and beneath a pair of welding heads indicated generally by reference numerals 47 and 48 to thereby weld the three strips of material in edge-to-edge relationship as in the same manner discussed in connection with FIG. 1. After leaving the welding station indicated by reference numeral 50, the composite strip may or may not be subjected to an annealing heat treatment at the station 51 indicated in dotted lines. The composite stripthen passes into the rolling station indiacted reference numeral 52 and passes between the pairs of rollers 53 to thereby reduce the thickness of the composite sheet to the desired gauge.

The particular construction of the composite strip in this case serves the purpose as aforementioned of constraining the strip for movement in a straight line thereby preventing turning of the strip which generally occurs where a relatively soft material is disposed along one edge portion of the strip. Here, the two outermost strips of relatively hard material will prevent the intermediate relatively soft strip from curving as would otherwise occur.

The composite strip is then subjected to precipitation hardening at station 55, and in this case the composite strip will be treated for example at 600 F. for approximately two hours which, of course, will precipitation harden the Berylco 25 material of strips 41 and 42 while not substantially altering the physical characteristics of the intermediate strip 40 of brass.

The composite sheet then passes to the cutting station indicated generally by reference numeral 60, whereat suitable cutting means is provided for severing the composite strip along a out line extending longitudinally of the strip and bi-secting the strip as seen.

It will be noted that the width of intermediate strip 40 is substantially twice that of strips 41 and 42 individually such that when the final cut is made, a pair of composite strips will be provided, each of which includes a beryllium copper alloy portion and a brass portion of substantially equal extent. It will be seen that intermediate portion 49 is divided into the two portions 40' and 40 as the composite strip thereof.

Referring now to FIG. 3 of the drawing, a composite strip indicated generally by reference numeral 65 is illustrated, this composite strip being manufactured in a manner similar to that shown in FIG. 2 and including three separate members 66, 67 and 68 which are welded to one another. These three different materials may be chosen in accordance with the desired characteristics, and the materials will be chosen such that the heat treatment temperature ranges thereof are different thereby enabling one or more of the members to be heat treated without substantially altering another of the members.

For example, strip 66 may be Berylco 25 which has been precipitation hardened by heating the composite strip to 600 F. for two hours while strip 67 may be formed of steel and strip 68 may be formed of brass whereby strips 67 and 68 will not have their physical characteristics substantially altered by the heat treatment step.

Referring now to FIGS. 6 and 7, a further modified form of the invention is illustrated wherein a composite strip 70 includes three members 71, 72 and 73 which are welded to one another in the manner as illustrated in FIG. 2 of the drawings. In this case, the intermediate member 72 may be formed of a metallic substance which is a poor electrical conductor such as stainless steel while the two outer members 71 and 73 may be formed of a metallic substance which is a good electrical conductor such as Berylco 25. This composite strip may be employed for ultimately making a multiple switch arrangement, and a plurality of contacts indicated by dotted lines 75 are laid out on the composite strip as seen in FIG. 6. 7

Referring now to FIG. 7, a portion of a multiple switch which has been cut from the composite strip shown in FIG. 6 is illustrated. As seen in this figure, a plurality of separate contact members 76 are provided. The electrical contact members at the upper side of member 72 are electrically connected to one another While the electrical contact members at the lower side of intermediate member 72 are also electrically connected to one another. However, the upper electrical contacts are insulated from the lower electrical contacts by the intermeis cut along the center portion diate portion 72 which is formed of a poor electrically conductive material.

Accordingly, a multiple switch arrangement is thereby provided wherein two sets of contacts are insulated from one another.

It will be noted that in the composite strip as shown in FIG. 6, the heat treatment is again carried out at a temperature of 600 F. for approximately two hours thereby precipitation hardening the Berylco strip portions 71 and 73 while the heat treatment temperature range of the intermediate stainless steel strip 72 is in the range of approximately 1800" to 2100 F. such that the physical properties of the stainless steel strip will not be substantially altered.

It is apparent that the ultimate article which is cut from the composite strips in each case includes two or more portions of different metallic substances, these portions being rigidly attached to one another by welding along a narrow area, and one of the portions is precipitation hardened while another portion retains its normal physical characteristics which it has prior to precipitation hardening thereby providing a composite body means with two or more distinct portions of different characteristics.

It is apparent from the foregoing that there is provided a new and novel composite product and method of manufacture thereof wherein a unique article is provided having distinct portions thereof of diflerent physical characteristics. The method is such as to provide a distinct demarcation of the portions of ditferent physical characteristics. Two or more metallic portions are welded to one another and then heat-treated so as to obtain the desired properties of one portion without altering the properties of another portion.

The method can be carried out at a rapid rate and substantially reduces the time, expense and effort involved in forming a composite product according to the present invention.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, and since the scope of the invention is defined by the appended claims, all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by those claims.

We claim:

1. The method of forming a composite product comprising at least two members including the steps of providing a first member formed of a beryllium copper alloy having a chemical composition by weight of beryllium in the range of 0.40 percent to 2.05 percent, cobalt in the range of 0.20 percent to 2.70 percent, the balance being copper, providing a second member selected from the group consisting of steel and brass, said first member having a heat treatment range substantially less than the heat treatment range of said second member, placing said first and second members in edge-to-edge relationship with one another, welding the edge portions together along a narrow area so as to provide a composite body having distinct portions of different metallic composition, rolling said composite body, heat treating the composite body in the precipitation hardening heat treatment range of the beryllium copper alloy of the first member and substantially below the heat treatment range of said second member, said heat treating being carried out at a temperature in the range of approximately 500 to 950 F. for a time in the range of 30 minutes to 3 hours to increase the strength, hardness and electrical conductivity of the first member without substantially altering the physical characteristics of the second member.

2. The method as defined in claim 1, wherein the beryllium copper alloy has a chemical composition by weight of beryllium in the range of 1.80 percent to 2.05 percent, cobalt in the range of 0.20 percent to 0.30 percent, the balance being copper, and the second member being steel, the composite body being heat treated in the range of approximately 550 F. to 650 F. for approximately two hours.

3. The method as defined in claim 1, wherein the beryllium copper alloy has a chemical composition by Weight of beryllium in the range of 0.40 percent to 0.70 percent, cobalt in the range of 2.35 percent to 2.70 percent, the balance being copper, and the second member being steel, the composite body being heat treated in the range of approximately 900 F. to 950 F. for approximately two hours.

4. The method as defined in claim 1, wherein the beryllium copper alloy has a chemical composition by weight of beryllium in the range of 1.80 percent to 2.05 percent, cobalt in the range of 0.20 percent to 0.30 percent, the balance being copper, and the second member being brass, the composite body being heat treated in the range of approximately 550 F. to 650 F. for approximately two hours.

5. The method as defined in claim 1, including the additional step of severing the composite product to provide a body means including at least two distinct portions of different physical characteristics.

6. The method of forming a composite product comprising at least two members including the steps of providing a first member formed of a beryllium copper alloy having a chemical composition by weight of beryllium in the range of 1.80 percent to 2.05 percent, cobalt in the range of 0.20 percent to 0.30 percent, the balance being copper, providing a second member having a chemical composition by weight of beryllium in the range of 0.40 percent to 0.70 percent, cobalt in the range of 2.35 percent to 2.70 percent, the balance being copper, said first member having a heat treatment range substantially less than the heat treatment range of said second member, placing said first and second members in edgeto-edge relationship with one another, welding the edge portions together along a narrow area so as to provide a composite body having distinct portions of different metallic composition, rolling said composite body, heat treating the composite body in the precipitation hardening heat treatment range of the first member and substantially below the heat treatment range of said second member, said heat treating being carried out at a temperature in the range of approximately 550 to 650 F. for approximately two hours to increase the strength, hardness, and electrical conductivity of the first member without substantially altering the physical characteristics of the second member.

References Cited in the file of this patent UNITED STATES PATENTS 2,125,153 Chace July 26, 1938 2,433,687 Drust Dec. 30, 1947 2,458,552 Blattner Jan. 1, 1949 2,486,285 Hurst Oct. 25, 1949 

1. THE METHOD OF FORMING A COMPOSITE PRODUCT COMPRISING AT LEAST TWO MEMBERS INCLUDING THE STEPS OF PROVIDING A FIRST MEMBER FORMED OF A BERYLLIUM COPPER ALLOY HAVING A CHEMICAL COMPOSITION BY WEIGHT OF BERYLLIUM IN THE RANGE OF 0.40 PERCENT TO 2.05 PERCENT, COBALT IN THE RANGE OF 0.20 PERCENT TO 2.70 PERCENT, THE BALANCE BEING COPPER, PROVIDING A SECOND MEMBER SELECTED FROM THE GROUP CONSISTING OF STEEL AND BRASS, SAID FIRST MEMBER HAVING A HEAT TREATMENT RANGE SUBSTANTIALLY LESS THAN THE HEAT TREATMENT RANGE OF SAID SECOND MEMBER, PLACING SAID FIRST AND SECOND MEMBERS IN EDGE-TO-EDGE RELATIONSHIP WITH ONE ANOTHER, WELDING THE EDGE PORTIONS TOGETHER ALONG A NARROW AREA SO AS TO PROVIDE A COMPOSITE BODY HAVING 